Method of eosgimtg ibsitlatok caps



July24, 1928. 1,678,594 G. H. HIGGINS" IETHOD OF FORGING INSULTOR CAPS Filed'oct. 27, 1927 25119613 31196? 1 GEORGE H. mecms INVENTOR. o W

ATTORNEY July 24, 1928.

G. HvHIGGINS IIETHOD 0F FORGING-INSULATOR cars Filed Oct. 27, 1927 2 Sheets-Sheet GEORG H. HIGGINS NVENTOR.

BY A L ATTORNEY Fetented July 24, 1925.

UNITED STATES GEORGE H. HIGGLKNSY 03. CORTLAND, NEW

YORK, ASSIGNOE T0 THE BREWER-- TXTGHENER DQRLEOBKTION. CORTLAND, NE" 'iZ'QZ-I I, J3. CJEEGHATION OF NEW METHOD OF FORGIE'G INSJ'ULATOR CAPS.

Application filed. October 27, 1927.

This invention relates to the art of hollow metal torgings and more particularly to a one-piece cap or socket adapted to securely mount therein an insulator disc of the suspension type as used. in connection with high-tension electric transmission lines or the like. The primary object of my improved method is to etl'ectively and econourically make a chan'ibered product of this character by a. con'ibined solid forging and eiq'ianding process as distinguished. 'troin the same article made by means oi" a casting process or complete forging; process.

Insulator caps of the suspension type are generally termed in the shape of an openniouthed bell of which its dome is cquipt with an integral attachment means that erves ior supperting purposes while the interior of such a hollow cap is iiisually provided with an undercut rnouth lip or riin means adapted to secure a cement medium and msitively hold the neck of an insulator disc within the cap socket.

protective cap ot this kind is ordinarily interposed between each of a. series of spaced. i'ui'ilti 'i e iu:-:ulator units mounted in tandem and the ni'unber oi units so strung together bei dependent upon the transmitted high tension line voltage; it will be obvious that the metal spacing caps in question must pos-- sess the utmost of reliability as to structural. u'iaterial tor the reason that it has proven. extr mely ditlicult as well as expensive to re ice any detective cap once it has been placed in. service.

The present invention seeks to promote the y and uniformity of such PIOClUC'S by is of an improved fo 5 process. The use 15 worked ine'tal insulator caps particuarly waen forged of high grade carbon or alloy steel. allows of making their wall tl'iickness relatively thin owing to the tiner and clo er grain that results troin swaging the metal; it also ai'lords a more unitorni and stronger molecular material structure than is attainable by casting methods. In addition. my forging method reduces the material and shipping weight required for safely carrying a specified suspended. line oad and, generally makes for a more conipact insulator assembly as compared with he cast tvpe of cap.

l pres 'ggl' invention in certain particu FSerial NO. 229177.

lars represents an improvement in method and construction over the disclosure made in the Clintoi'i \V. tover Patent No. 1,4r63,601 as granted July 31, 1923. To this end and the accomplishment of other new and useful results, my invention further consists in novel it'catures of structure and manipulation. all of which will hereinafter be more fully described.

Reference had to the accompanying two sheets of drawings which are illustrative of a specific embodiment 0t my invention par ticularly as applied to torged insulator caps of the socket type, in which drawings like characters oi retertaice indicate like parts, and in which:

Fig.1. 1 represents an assembly of: a series of alternate insulator discs arranged in tandent each interconnected by means of my interposed cap devices and intended as a whole to suspend. a high tension transmission line.

Fig. 2 shows an enlarged transverse sectionai view as taken through one of the tandein insulator units indicated in Fig. 1.

Fig. 3 illustrates in perspective, one shape oi stock from which my cap may be forged. Fig. 1 shows in plan blank comprising a flanged. disc provided with a centrally truded support lug that may initially be shaped. up out of said stock, while Fig. shows a section thereof as taken along line 5' 5 of Fig. l.

Fig. 6 indicates the nranner in which the circuinscribing flange portion of said blank rnay next be orawn up into a cup-shape whose skirt provided with a relatively a i mouth dimension.

Fi 7 shows how t s mouth may be undercut by expandu outwardl the skirt portion that lies con. queue to the cup riin, while Figs. 8 and 9 show the respective circular end view contours thereof. i

Fig. 10 illustrates rolling" method by which the indercutting ot the cup mouth may readily be accomplished by an expanding operation.

Fig". 11. shows the manner in which my integral supporting; lug: may be recessed to fashion same a socket type of insulator cap, and 12 shows a top view oi said socketrecess thus formed.

views of an alternative method of shaping up my solid supporting lug which is here cut into two spaced ear lugs or straps for hanger attachment purposes.

Rel'erring first to Fig. 1, this shows a series of miiltiple insulator discs such as A, A, etc. of which the uppermost one may be suspended in any suitable manner from a cross arm Cat or the like as carried by a pole or transmission line tower; these discs may be respectively interconnected in tandem by means ot the interposed chambered metal caps B, B, etc. which cooperate with complementary link members C2 to form a built-up composite insulator in the conven tional fashion and of which the lowermost disc is usually provided with a conductor clamp Cl that carries the high tension transmission wire C3.

2 shows in enlarged scale, the principal structural features of one such insulator unit and it will be observed that any intermediate metal cap suchas B is provided with a flared tubular skirt portion F13 and that each such cap may be further equipt with an integrally formed supporting lug means such as E2 which in the present in stance, is shown as of the socket type. The mouth or lip edge of said bell-shaped cap is equipt with an undercut rim mcn'iber E4 adapted to snugly receive and mount the neck A1 of the glass, porcelain or similar style of petticoat insulator disc A. This disc may further be provided with a centrally disposed isc socket 212" into which the free shank end of the headed link pin C2 may be lirn'ily cemented or otherwise secured, while the insulator neck it may likewise be fastened into the radially undercut. cap cavity or socket, preferably by means of cement or other suitable filler medium indicated A3". In close adjac ncy to the restricted rim Ed there is provided an internally disposed groove E3 that extends radially beyond the final dimension given to the rim mouth of my cap so a; to afford an underciiit chamber into which said cement medium may be poured and allowed to set; whereupon because of its enlarged shear area, said cement is made capable of safely resisting neck displacement against a heavy line load. The dome of my cap is preferabl i secured to the lowerend of its suspending link through a pivot type of joint about which the cap may oscillate.

up now the making of a cap structure by my improved forging process the first step may reside in rough forging down the bar or plate stock D illustrated in Fig. 3 or the like into a relatively thin blank I 1 represented by 4i and 5. Said blank shows a pancake like or disc portion E1 whose central portion extruded into a somewhat rounded projecting lug member E2 and which particular gathering of the metal is subsequently utilized to form an integral support means for my finished insulator cap. If desired, said fiat disc portion E1 may initially be given a tiered or an upwardly dished profile marked E1 and it will be understood that either of such blank shapes are intended to be forged up by means of suitable dies.

The surrounding disc portion ltllt of my blank may now be bent or drawn up into the cap shape shown in Fig. 6 and this step may either be performed by n ans of a single or successive stage cold drawing proc 'css through the use of suitable press equipt with the necessary dies, it is preferred however to perform this step by a hot forging process in a single heat with the initial formation of said blank; should the latter method be resorted to, the forging of said bar or plate stock D by the gang method into the successive forms shown in Figs. l to 6 inclusive, virtually constitutes a single or primary shaping operation or step. As will be apparent. the end in view is to fashion the forged metal into the cup shape that is represented in Fig. 6 in which the flared disc portion El has been brought up into the tubular cup-like skirt portion l l l that terminates in the rim Eatand which skirt preferably conforms to substantially straight-line diverging profile having a relatively small mouth opening or initial inside rim dimension deuiguzted as M. The opposite end of said skirt port on l l l is closed by the ransverec dome or rown wall portions ill); near the center of the exterior surface of said dome wall, there ix integrally attached the lug E2 originally shaped up with said blank, it being pointed out that the integral formation of the sup port element of my swaged insulator cap constitutes an important feature of the present nvention.

As a further step in the making of my insulator cap, said rim E lnow undercut in a single expanding operation in the fashion cross-sectionally represented in F "I. The circumferential skirt wall E3 portion lying contiguous to the cap month has there by been swaged radially outward by means of the indented bulge E3 to constitute an undercut endless groove with respect to the original straightdine profile shape of said skirt wall that is indicated by dotted and dashed outline. This particular step may be performed by any suitable expanding method but it is preferred to use complementary inside and outside rolls, surh tor instance as F1 and F2 that are schemal cally represented in Fig. 10; the complementary peripheries of these rolls are properli shaped to expand said straight sl' profile into the interiorly bulged p: o; i: described in connection with Fig. 7 311' lit) all)

inside roll Fl. may be given a relatively small diameter as indicated and made laterally movable for the purpose of exerting a heavy follow-up thrust against the outer roller F2 or backing member that rotates in the fixedly held bushing F 8.

It is emphasized however that the essential element of my described skirt expanding means resides in said inner roller means Fl which forming or spinning implement when inserted into the mouth M of a cup shape, is adopted to apply radially directed pressure against the interior of said skirt and thus in a single operation, roll outthe endless channel-like groove E8 disposed in.- wardly of the rim E l.

It will further be observed that the inner diameter M given to the rim mouth may be kept fixed once the disc E1 is bent up into the shape shown in F 6, and that this sized neck diameter need not thereafter be disturbed by the expanding operation such as would apply when operating in a reverse manner in accordance with the Stover patent method where the mouth of his forged cap is finally cupped inwardly to form. an undercut that subsequently llPLQS the inside diameter of his contracted neck mouth. After my cap has been internally grooved by the cited expanding or bulging method, the rim may if desired, be trimmed down to form a finished rim mouth Ed as indicated in Fig. 7, it being apparent that the cross-sectional. shape .of cap here shown is rcpresei'itative of a plane ligure that by its revolution about the axes X-X, preferably generates a syn'in'ietrically shaped cap cavity or socket chamber.

Finally, the lug E2 of my completely forged and expanded cap may be machined to form up a socket chamber E6 such for instance is shown in Figs. 11 and 12. and this may be milled or hot sawed out of the solid dome lug. This particular style of lug socket is intended to cooperate for eap support purposes with a link pin C2 having a rounded or ball head enlargement C2 which is adapted to be removably received Within said undercut socket E6 and to engage with the overhanging ledge portions E2 thereof, in the ball and socket manner represented in 2. In order to secure said head against inadvertent displacement, the cotter pin E7 may be inserted through the drilled hole E8 of the hollowed lug.

As an alternative support means, said or;- truded lug E2 may if preferred, be given a slightly modified. shape to allow of its being machine slotted into the complementary spaced dome ears E9 and E9 as indicated in Figs. 1.3 to 15; these cars may thereupon be drilled to mount the through toggle pin E10 that engages with a somewhat different type of link pin 2 which in this instance, is

provided with a journaled stub-end enlargement C2" of the clevis type.

Both the described socket or car types 0:" cap supports are now in common use, and my invention in part consists in integrally forming either of such attaching means by improved one-piece swage methods and in which the lug E2 may be merged by the use of ample fillets such E2 which afford a perfectly smooth exterior that can readily be uniformly and flawlessly galvanized throughout all ofthe exposed cap surfaces for rust preventive purposes. The filleted integral tie of my support lug obviates all inaccessible pockets or crevices such as would have to be contended with were said lug ears or sockets separately fabricated and then. attached by welding or rivet means, it being apparent that any such surface irregularities are difficult to gal vanizo evenly with an unbroken protective coating capable of withstanding prolonged weathering. In addition, my it'orged insulator cap allows of keeping the crown or dome wall E5 relatively thin which in turn holds the overall height dimension at a minimum; the smooth interior of my cap not only facilitates the secure and compact mounting of the insulator neck into the cap recess but the avoidance of any sharp projections near the cap mouth, augments the dielectric breakdown resistance against high-tension voltage.

Furthermore, I am able to closely maiir tain said inside or mouth diameter M to any predetermined dimension and that owing to the superior quality of the swaged cap metal, its ultimate holding power against a severe pull load is unexcolled; any waste by defective caps is also mate rially reduced over that prevailing in the manufacture of the cast type of caps and the chances for hidden defects getting by on inspeefon. are decidedly remote because well made articles of the forged type generally enjoy a striking reputation for reliability and uniformity of product. My described method therefore allows of producing a finished insulator cap that is of the highest grade and one that is in all respects admirably suited to the intended purposes.

scope of my invention heretofore described and more particularly pointed out in the appended claims.

I claim- 1. The method of making from bar or plate stock, a one-piece supportable insulator cap of the undercut socket type or the like, and which method consists in swaging up said stock into a cup-like shape comprising a tubular sxirt portion having an open lip end with the other end thereof closed by a crown wall provided with an exteriorly extruded supporting lug means, and then introducing therein a groove forming imple ment which by virtue of a radially exerted swage pressure is adapted to expand the lip region of said skirt into an outwardly bulged groove that is radially undercut with respect to the final lip end opening of said skirt. v

2. The method of making from bar or plate stock, a one-piece supportable insulator cap of the undercut socket type or the like, and which method includes forming said stock into a cup-like shape comprising a tubular skirt portion of which the open rim end is brought to a predetermined mouth dimension while the other skirt end is closed by a dome wall portion from the exterior surface of which dome there is extruded a lug means adapted to support said cap, and then introducing into said mouth a forming implement which by the application of interiorly applied surface pressure is adapted in a single operation to bulge out the skirt region contiguous to said rim into a ehannellike groove means that extends radially beyond the final mouth dimension.

3. The method of making from bar or plate stock, a one-piece supportable insulator cap of the undercut socket type or the like, and which method includes forming said stock into a cuplike shape comprising a tapered tubular skirt portion having a substantially straight-line cross-sectional profile and of which skirt its larger end is kept open to constitute a mouth while the smaller skirt end is closed by a dome wall portion carrying an exteriorly extruded lug means for cap supportin purposes, and

thereupon introducing into said mouth a forming implement including a roller means adapted to expand outwardly the rim region of said skirt into a undercut groove means that extends radially beyond the final mouth dimension of said skirt.

4. The method of making from bar or plate stock, a onepiece supportable insulator cap of the undercut socket type or the like, and which method includes swaging said stock into a disclike blank provided with an extruded cap supporting lug means that projects out of one disc face near the center thereof, then bendnig up the lug encircling disc portion into a cup-like shape comprising a tubular skirt portion having a mouthed rim end while the other skirt end is closed by a dome wall portion with said extruded lug disposed to project from the exterior surface thereof, and lastly, introducing therein a forming implement adapted to expand outwardly the rim region of said skirt into a channel-like groove that is radially undercut with respect to the final rim mouth dimension,

5. The method of making from bar or plate stock, a one-piece supportable insulator cap of the undercut socket type or the like adapted to be supported by link pin means, and which method includes forming said stock into a cup-like shape comprising a tubular skirt portion having a mouthed rim end while the other skirt end is closed by a dome wall portion from the exterior surface of which an extruded solid cap sup porting lug means projects, then introducing a pressure exerting implement into the rim mouth which upon relative rotation between said implement and the skirt is adapted to roll outwardly the rim region of said skirt into an endless channel-like groove that is radially undercut with respect to the final rim mouth dimension, and lastly, trimming oil a portion of the tubular skirt rim that extends beyond the outermost of said channel edges.

6. The process of making from bar or plate stock, a one-piece supportable insulator cap of the undercut socket type and securely mounting therein an insulator disc neck, said process includin forming said stock into a cup-like shape comprising a tubular skirt portion having a mouthed rim end while the other end is closed by a dome wall portion from the exterior surface of which dome there extruded an integral lug means adapted to support said cap, and thereupon introducing a pressure exerting implement adapted to bulge out the skirt region contiguous to said rim and generate an endless undercut groove means that extends radially beyond the final expanded dimension given to said mouth.

'7. The method of making from bar or plate stock, a one-piece supportable insulator cap of the undercut socket type or the like provided with smooth exterior and interior surfaces, and which method includes hot forging said stock into a cup-likc shape comprising a tubular skirt portion having a mouthed rim end while the other skirt end is closed by a rounded dome wall portion from the exterior surface of which dome there is extruded an integrally filleted lug means, then introducing a forming implement serving to exert radial pressure against the interior of the rim region of said skirt and which implement is adapted in a single operation to expand an undercut groove means that is radially undercut with respect to the final mouth opening of said erted upon the skirt interior is adapted in a skirt. single operation to expand the mouth of the 8. The method of making an insulator cup into an undereutbeed disposed inwardly 1 cap from a blank bar which includes forgof the cup edge.

ing a cup and extruding an ear lug on its In testimony whereof, I have herewith bottom and then introducing a groove formset my hand this 26th day of October, 1927. ing implement Which by radial pressure ex- GEORGE H. HIGGINS. 

